Outdoor emergency sirens went off overnight and early this morning in several San Francisco neighborhoods, but there is not a known emergency in The City, according to the Department of Emergency Management. Officials said alarms went off around 11 p.m. Saturday in the Bernal Heights, Noe Valley and Hunters Point neighborhoods, the Bayview District, City Hall, and other areas, but there was no known emergency that would have triggered the alarms. Alarms around The City went off again around 5 a.m. today. Crews have been dispatched to investigate the status of the sirens and to conduct testing. The Department of Emergency Management said it may be possible that the alarms will go off again during the testing. Officials said several people called 911 to report the sirens, and dispatch centers have been notified about the alarms going off.